Functional element, method of manufacturing functional element, electronic apparatus, and mobile object

ABSTRACT

A functional element includes a first base body; a coupling section which is coupled to the first base body; a support body which extends from the coupling section; a mass body which is coupled to the support body; a drive electrode which is provided on a surface side that faces the mass body; a detection working electrode which extends from the support body; and a detection fixed electrode which is coupled to the first base body and faces at least a portion of the detection working electrode. The mass body can be displaced in a direction which intersects a main surface of the mass body. When a distance between the first base body and the mass body is referred to as d1 and a distance between the first base body and the detection fixed electrode is referred to as d2, a relation of d1&gt;d2 is satisfied.

BACKGROUND

1. Technical Field

The present invention relates to a functional element, a method ofmanufacturing a functional element, an electronic apparatus including afunctional element, and a mobile object.

2. Related Art

In recent years, an angular velocity sensor (Gyro sensor) which is usedas a functional element that detects angular velocity using, forexample, a silicon micro electro mechanical system (MEMS) has beendeveloped, and is used for a body control of a vehicle, a vehicleposition detection of a car navigation system, vibration controlcorrection (so-called, hand shake correction) of a digital camera, avideo camera, and a mobile phone, or the like.

In U.S. Pat. No. 6,067,858, an angular velocity sensor is disclosed inwhich when a mass body is driven by vibration, a so-called verticalvibration in a direction that intersects a main surface of the massbody, and in a planar view, angular velocity of axis rotation in adirection along the main surface of the mass body is applied, the massbody is vibrated in another direction along the main surface by Coriolisforce, and angular velocity of an internal surface axis rotation isdetected by a change of a capacitance which is generated between aworking electrode which extends from the mass body, and a fixedelectrode which is disposed on a support substrate.

However, in the angular velocity sensor described in U.S. Pat. No.6,067,858, if a mass body is driven by a vertical vibration, an intervalbetween a support base body and the mass body is decreased, and thus itis not possible to have a large amount of displacement (amplitude) ofthe mass body. For this reason, there is a problem in which detectionsensitivity is not high.

SUMMARY

The invention can be realized as the following forms or applicationexamples.

APPLICATION EXAMPLE 1

According to this application example, there is provided a functionalelement including a first base body; a coupling section which is coupledto the first base body; a support body which extends from the couplingsection; a mass body which is coupled to the support body; a driveelectrode which is provided on a surface side that faces the mass bodyof the first base body; a detection working electrode which extends fromthe support body; and a detection fixed electrode which is coupled tothe first base body and faces at least a portion of the detectionworking electrode, in which the mass body can be displaced in adirection which intersects a main surface of the mass body, and inwhich, when a distance between the first base body and the mass body isreferred to as d1 and a distance between the first base body and thedetection fixed electrode is referred to as d2, a relation of d1>d2 issatisfied.

In this case, the mass body can be displaced in a direction whichintersects the main surface, and thereby the mass body can be easilydriven by the vertical vibration which is vibration in a direction whichintersects the main surface. In addition, the distance d1 between thefirst base body and the mass body is longer than the distance d2 betweenthe first base body and the detection fixed electrode, and thereby themass body which is driven by the vertical vibration can perform a largevibration displacement in a direction which intersects the main surface.Thus, since the mass body can be driven by the vertical vibration havinga large vibration displacement (amplitude), in a case in which angularvelocity of an internal surface axis rotation is applied, a largeCoriolis force acts, an amount of change of a capacitance that isgenerated between the detection working electrode and the detectionfixed electrode is increased, and thus it is possible to obtain thefunctional element having high detection sensitivity with respect toangular velocity of the internal surface axis rotation.

APPLICATION EXAMPLE 2

In the functional element according to the application example, it ispreferable that a thick body section is provided in the first base body,the coupling section is provided in the thick body section, and in aplanar view, the mass body and the thick body section are separated fromeach other.

In this case, the mass body is disposed on an upper surface of the thickbody section of the first base body through the coupling section, andthereby the mass body can perform a larger vibration displacement up toa distance in which a height of the thick body section extending fromthe first base body is added to the distance d1 between the first basebody and the mass body. In addition, since the mass body and the thickbody section are separated from each other in a planar view, the massbody can vibrate without being in contact with the thick body section.

APPLICATION EXAMPLE 3

In the functional element according to the application example, it ispreferable that at least a portion of the detection fixed electrode isprovided in the thick body section.

In this case, since the detection fixed electrode is provided on thethick body section of the first base body, the detection fixedelectrode, and the detection working electrode which extends from thesupport body that is disposed on the thick body section of the firstbase body through the coupling section can be disposed so as to faceeach other, and thereby a capacitance can be formed between thedetection working electrode and the detection fixed electrode.

APPLICATION EXAMPLE 4

In the functional element according to the application example, it ispreferable that a thickness of the detection working electrode isthicker than that of the mass body.

In this case, a thickness of the detection working electrode is thickerthan that of the mass body, and thereby it is possible to lengthen adistance in which a main surface of the mass body and a main surface ofthe first base body face each other, and to increase an area in whichthe detection working electrode and the detection fixed electrode faceeach other. That is, while vibration displacement of the mass body isincreased, a capacitance between the detection working electrode and thedetection fixed electrode which are electrodes for detection can beincreased, and it is possible to obtain the functional element havinghigh detection sensitivity.

APPLICATION EXAMPLE 5

In the functional element according to the application example, it ispreferable that, when the mass body is vibrated by an AC voltage whichis applied between the mass body and the drive electrode, and angularvelocity of axis rotation in a direction along the main surface of themass body and the direction in which the detection working electrodeextends is applied to the mass body, the detection working electrodevibrates in a direction which intersects the direction.

In this case, by Coriolis force which is generated by angular velocityof an internal surface axis rotation, the mass body performs vibrationdisplacement in a direction that intersects a direction in which thedetection working electrode extends, and thereby the detection workingelectrode that extends from the support body which is coupled to themass body also performs vibration displacement in the same direction asthe mass body, and an interval between the detection fixed electrode andthe detection working electrode is changed. For this reason, acapacitance between the detection working electrode and the detectionfixed electrode is changed, and thereby angular velocity of the internalsurface axis rotation can be detected by measuring an amount of changeof the capacitance between the electrodes. That is, the functionalelement can be used as an angular velocity sensor which detects angularvelocity of the internal surface axis rotation.

APPLICATION EXAMPLE 6

In the functional element according to the application example, it ispreferable that the support body includes a first elasticity sectionwhich is coupled to the coupling section, and a second elasticitysection which is coupled to the mass body, and a thickness of the firstelasticity section is thicker than a thickness of the second elasticitysection, in a sectional view.

In this case, since a thickness of the first elasticity section isthicker than a thickness of the second elasticity section in a sectionalview, a bending stiffness in a thickness direction of the firstelasticity section is higher than that of the second elasticity section,and thereby, based on vibration in which the mass body performsvibration displacement in a direction that intersects a main surface, itis possible to suppress that the detection working electrode which iscoupled to the support body performs vibration displacement in thedirection that intersects a main surface.

APPLICATION EXAMPLE 7

According to this application example, there is provided a method ofmanufacturing a functional element including forming a second concavesection in a second base body by processing the second base body;disposing a drive electrode on a first base body; bonding together asurface having the second concave section which is provided in thesecond base body and a surface having the drive electrode of the firstbase body; and forming a coupling section, a support body, a mass body,a detection working electrode, and a detection fixed electrode byprocessing the second base body, in which, the forming of the couplingsection, the support body, the mass body, the detection workingelectrode, and the detection fixed electrode includes forming the massbody in the second concave section.

In this case, since the mass body is formed in the second concavesection, a distance between a main surface of the mass body and a mainsurface of the first base body can be lengthened, the mass body canperform a large vibration displacement in a direction which intersectsthe main surface of the mass body, and thereby it is possible tomanufacture the functional element having high detection sensitivity.

APPLICATION EXAMPLE 8

In the method of manufacturing a functional element according to theapplication example, it is preferable that the method further includesforming a first concave section in the first base body, the disposing ofthe drive electrode includes forming the drive electrode in the firstconcave section, and the bonding includes bonding together the firstconcave section and the second concave section so as to face each other.

In this case, since the drive electrode is formed in the first concavesection, and the first concave section and the second concave sectionare bonded together so as to face each other, the mass body and thedrive electrode can be disposed so as to face each other, a gap area inwhich the mass body can perform vibration displacement is furtherwidened, the mass body can perform a larger vibration displacement in adirection which intersects a main surface, and thereby it is possible tomanufacture the functional element having high detection sensitivity.

APPLICATION EXAMPLE 9

According to this application example, there is provided an electronicapparatus including the functional element according to the aboveapplication examples.

According to the present application example, it is possible to realizean accurate electronic apparatus by providing a functional elementhaving high detection sensitivity.

APPLICATION EXAMPLE 10

According to this application example, there is provided a mobile objectincluding the functional element according to the above applicationexamples.

According to the present application example, it is possible to realizea mobile object having excellent safety by providing a functionalelement having high detection sensitivity.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a schematic plan diagram illustrating a schematic structure ofan angular velocity sensor according to the present embodiment.

FIG. 2 is a schematic sectional diagram taken along line II-II in FIG.1.

FIG. 3 is a schematic sectional diagram taken along line III-III in FIG.1.

FIG. 4 is a schematic sectional diagram illustrating an operation of anangular velocity sensor according to the present embodiment.

FIG. 5 is a schematic sectional diagram illustrating an operation of anangular velocity sensor according to the present embodiment.

FIG. 6 is a schematic sectional diagram illustrating an operation of anangular velocity sensor according to the present embodiment.

FIG. 7 is a schematic sectional diagram illustrating an operation of anangular velocity sensor according to the present embodiment.

FIG. 8 is a flowchart illustrating important manufacturing processes ofan angular velocity sensor according to the present embodiment.

FIG. 9 is a schematic sectional diagram illustrating a manufacturingprocess of an angular velocity sensor according to the presentembodiment.

FIG. 10 is a schematic sectional diagram illustrating a manufacturingprocess of an angular velocity sensor according to the presentembodiment.

FIG. 11 is a schematic sectional diagram illustrating a manufacturingprocess of an angular velocity sensor according to the presentembodiment.

FIG. 12 is a perspective diagram illustrating a schematic configurationof a personal computer of a mobile type as an example of an electronicapparatus.

FIG. 13 is a perspective diagram illustrating a schematic configurationof a mobile phone as an example of an electronic apparatus.

FIG. 14 is a perspective diagram illustrating a schematic configurationof a digital still camera as an example of an electronic apparatus.

FIG. 15 is a perspective diagram illustrating a schematic configurationof an automobile as an example of an electronic apparatus.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, embodiments of the invention will be described in detailwith reference to the drawings. In the respective figures which will bedescribed hereinafter, the respective configuration elements have amagnitude which can be substantially recognized, and thus there is acase in which dimensions and ratios of the respective configurationelements are described so as to be substantially different fromdimensions and ratios of actual configuration elements.

Functional Element

As an example of a functional element according to the presentembodiment, an angular velocity sensor which is driven by a verticalvibration and detects angular velocity of internal surface axis rotationwill be described with reference to drawings.

FIG. 1 is a schematic plan diagram illustrating a schematic structure ofan angular velocity sensor 100 which is used as a functional elementaccording to the present embodiment. FIG. 2 is a schematic sectionaldiagram taken along line II-II in FIG. 1. In addition, in the followingrespective figures, for convenience, as three axes which are orthogonalto one another, an X axis, a Y Axis, and a Z axis are illustrated, a tipside of an arrow which is illustrated is referred to as “+side”, and abase end side is referred to as “−side”. In addition, a direction whichis parallel to the X axis is referred to as an “X-axis direction”, adirection which is parallel to the Y axis is referred to as a “Y-axisdirection”, and a direction which is parallel to the Z axis is referredto as a “Z-axis direction”. Furthermore, for convenience, in a planarview which is viewed from the Z-axis direction, a surface of the Z-axisdirection will be described as a main surface, a +Z-axis side will bedescribed as an upper surface, and a −Z axis side will be described as alower surface.

The angular velocity sensor 100 according to the present embodiment hasa structure in which two structural bodies are arranged in parallel, andhas a configuration in which the two structural bodies areline-symmetrical to a center line C in FIG. 1. For this reason,description of the structural body on the +X direction side will beomitted, and a structure and an operation of the angular velocity sensor100 will be made using the structural body on the −X direction side.

The angular velocity sensor 100 is an angular velocity sensor(capacitance type MEMS angular velocity sensor element) which detectsangular velocity of a Y-axis rotation which is an internal surface axis,and as illustrated in FIG. 1 and FIG. 2, is configured to include afirst base body 10 which includes drive electrodes 27 in first concavesections 14, and a second base body 110 on which a mass body 60 and asupport body 20 are formed.

In the first base body 10, a thick body section 12 of a ring shape isprovided along an outer edge section of the first base body 10, and thefirst concave sections 14 are configured on a side which faces thesecond base body 110. That is, a bottom surface 16 is provided in thefirst concave section 14 of the first base body 10, and on an uppersurface of the bottom surface 16 which configures the first concavesection 14, a drive electrode 27 is formed in a position which faces themass body 60 that is provided on the second base body 110 which will bedescribed later.

A material of the first base body 10 is, for example, glass or silicon,and a material of the drive electrode 27 is, for example, aluminum,gold, indium tin oxide (ITO), or the like.

It is preferable that a material of the drive electrode 27 is atransparent electrode material such as ITO. By using a transparentelectrode material as the drive electrode 27, in a case in which thefirst base body 10 is a transparent substrate (glass substrate), foreignmatter or the like which exists on an upper surface of the driveelectrode 27 can be easily viewed from a lower surface side of the firstbase body 10.

The second base body 110 is configured to include coupling sections 22,the support body 20 which includes first elasticity sections 30 andsecond elasticity sections 24, a mass body 60, detection workingelectrodes 40, and detection fixed electrodes 50. In addition, in thesecond base body 110, a second concave section 15 is formed in the massbody 60 and the second elasticity sections 24 on a side facing the firstbase body 10.

The coupling section 22 is coupled to an upper surface of the thick bodysection 12 of the first base body 10. The coupling section 22 may befixed (bonded) to the upper surface of the thick body section 12. Thecoupling section 22 supports the support body 20 which extends from thecoupling section 22, and the mass body 60 and the detection workingelectrode 40 which are coupled to the support body 20. In the exampleillustrated in FIG. 1, four coupling sections 22 per one support body 20are provided, but if the support body 20 can support it, the number ofthe coupling sections 22 is not particularly limited.

The support body 20 has a ring shape which encloses the mass body 60,and is configured to include the first elasticity section 30 which iscoupled to the coupling section 22, and the second elasticity section 24which is coupled to the mass body 60.

The first elasticity section 30 extends from the coupling section 22 inthe Y-axis direction which is a direction that intersects a direction inwhich the mass bodies 60 are arranged in parallel, is coupled to thesupport body 20, and is configured so as to perform vibrationdisplacement of the support body 20 to which the mass body 60 and thedetection working electrode 40 are coupled, along the X-axis directionwhich is a direction in which the mass bodies 60 are arranged inparallel. In the example illustrated in FIG. 1, four first elasticitysections 30 per one support body 20 are provided, but if vibrationdisplacement of the support body 20 can be performed in the X-axisdirection, the number of the first elasticity sections 30 is notparticularly limited.

The second elasticity section 24 extends from the support body 20 in theY-axis direction, while reciprocating in the X-axis direction, iscoupled to the mass body 60, and is configured perform vibrationdisplacement of the mass body 60 only in the Z-axis direction, withoutvibration displacement of the support body 20 in the Z-axis direction.Thus, the second elasticity section 24 extends from the support body 20in the X-axis direction, while reciprocating in the Y-axis direction,and may be configured to be coupled to the mass body 60. In the exampleillustrated in FIG. 1, four second elasticity sections 24 per one massbody 60 are provided, but if vibration displacement of the mass body 60can be performed in the Z-axis direction which is a direction thatintersects a main surface, the number of the second elasticity sections24 is not particularly limited.

A thickness (length of Z-axis direction) of the first elasticity section30 is configured to be thicker than a thickness (length of Z-axisdirection) of the second elasticity section 24, in a sectional view.That is, as illustrated in FIG. 2, the second elasticity section 24 isformed in the second concave section 15 which is formed in the secondbase body 110, and thereby the first elasticity section 30 can bethicker than the second elasticity section 24. For this reason, abending stiffness in the Z-axis direction which is a thickness directionof the first elasticity section 30 is stronger than the secondelasticity section 24, and thus it is possible to suppress vibrationdisplacement of the detection working electrode 40, which is coupled tothe support body 20, in the Z-axis direction, by vibration in whichvibration displacement of the mass body 60 is performed in the Z-axisdirection.

The mass body 60 is coupled to the support body 20 through the secondelasticity section 24. For this reason, bending stiffness in the Z-axisdirection is supported by a low second elasticity section 24, and thusthe mass body 60 is configured so as to perform vibration displacementin the Z-axis direction which is a direction that intersects a mainsurface. For this reason, by being supported by the second elasticitysection 24 in which vibration displacement is easily performed in theZ-axis direction, the mass body 60 can be displaced in the Z-axisdirection. A thickness (length of Z-axis direction) of the mass body 60,as illustrated in FIG. 2, is provided in the second concave section 15which is formed in the second base body 110, and thus, is thinner than athickness (length of Z-axis direction) of the support body 20 and thedetection working electrode 40 which extends from the support body 20.In the example illustrated in FIG. 1, a planar shape of the mass body 60is a rectangular shape, but may be a polygonal shape or a circularshape.

The detection working electrodes 40 extend from the support body 20 inthe Y-axis direction, and in the example illustrated in FIG. 1,respectively extend from a side opposite to a side to which the secondelasticity section 24 of the support body 20 is coupled, in a +Y-axisdirection and a −Y-axis direction.

The detection fixed electrode 50 is coupled to an upper surface of thethick body section 12 which is an upper surface of the first base body10. The detection fixed electrode 50 may be fixed (bonded) to the uppersurface of the thick body section 12. The detection fixed electrode 50extends from a side which is coupled to the thick body section 12 in theY-axis direction, and faces the detection working electrode 40 through agap. In the example illustrated in FIG. 1, a detection fixed electrode50 b is provided on a −X-axis direction side of the detection workingelectrode 40, and a detection fixed electrode 50 a is provided on a+X-axis direction side of the detection working electrode 40.

The detection fixed electrode 50 faces the detection working electrode40 in the X-axis direction. A side surface (a surface which faces theX-axis direction) of the detection fixed electrode 50 is in parallelwith, for example, a side surface (a surface which faces the X-axisdirection) of the detection working electrode 40. The side surface ofthe detection fixed electrode 50 and the side surface of the detectionworking electrode 40 may be in parallel with a YZ-axis surface which isorthogonal to the X axis.

The support body 20 which includes the first elasticity section 30 andthe second elasticity section 24, the mass body 60, and the detectionworking electrode 40 which are disposed on the first concave section 14of the first base body 10, and are separated from the first base body10, by the coupling section 22 which is coupled to an upper surface ofthe thick body section 12 of the first base body 10. The mass body 60 isformed in the second concave section 15 of the second base body 110.Here, a distance d1 between the first base body 10 and the mass body 60is longer than a distance d2 between the first base body 10 and thedetection fixed electrode 50. For this reason, the mass body 60 canperform a large vibration displacement in the Z-axis direction which isa direction that is orthogonal to a main surface.

The mass body 60 and the drive electrode 27 are disposed so as to faceeach other, and thereby if a voltage is applied to the mass body 60 andthe drive electrode 27, electrostatic force is generated between themass body 60 and the drive electrode 27, vibration can be produced byrepeating approach and separation of the mass body 60 on the driveelectrode 27 side. By doing this, it is possible to perform a verticalvibration of the mass body 60 in the Z-axis direction.

The mass body 60 vibrates in the Z-axis direction by an AC voltage whichis applied between the mass body 60 and the drive electrode 27, and whenangular velocity of Y-axis rotation is applied in the Y-axis directionwhich is a direction in which the detection working electrode 40extends, Coriolis force is applied to the mass body 60, and the massbody 60 performs vibration displacement in the X-axis direction. Thatis, in a state in which the mass body 60 vibrates in the Z-axisdirection, if angular velocity of Y-axis rotation is applied, theColiolis force is applied to the mass body 60, the mass body 60 performsvibration displacement in the X-axis direction, and thus the detectionworking electrode 40 which is coupled to the mass body 60 through thesupport body 20 also performs vibration displacement in the samedirection as that of the mass body 60. For this reason, by measuring acapacitance between the detection working electrode 40 and the detectionfixed electrode 50, angular velocity can be detected, and thereby it ispossible to obtain a function as an angular velocity sensor 100.

The materials of the coupling section 22 of the second base body 110,the support body 20 which includes the first elasticity section 30 andthe second elasticity section 24, the mass body 60, the detectionworking electrode 40, and the detection fixed electrode 50 are siliconto which conductivity is added by doping impurities, such as phosphorus,or boron. The coupling section 22 of the second base body 110, thesupport body 20 which includes the first elasticity section 30 and thesecond elasticity section 24, the mass body 60, the detection workingelectrode 40, and the detection fixed electrode 50 are formed byintegrally processing one substrate (for example, silicon substrate)using a photolithography method and an etching method.

A method of bonding the coupling section 22 and the detection fixedelectrode 50 of the second base body 110 to the first base body 10 isnot particularly limited, and for example, in a case in which a materialof the first base body 10 is glass and a material of the couplingsection 22 and the detection fixed electrode 50 of the second base body110 is silicon, the first base body 10 can be anodically bonded to thecoupling section 22 and the detection fixed electrode 50 of the secondbase body 110.

Operation Principle of Functional Element

Next, an operation principle of the angular velocity sensor 100 that isused as a functional element will be described in detail using FIG. 1and FIG. 3 to FIG. 7.

FIG. 3 is a schematic sectional diagram taken along the line III-III inFIG. 1. FIG. 4 to FIG. 7 are schematic sectional diagrams illustratingan operation of the angular velocity sensor 100 according to the presentembodiment. FIG. 3 illustrates a structure in which the angular velocitysensor 100 is line-symmectric to a center line D, and thus FIG. 4 toFIG. 7 illustrate only structural bodies on the −X axis side of FIG. 3,and operations thereof will be described.

If a voltage is applied to the mass body 60 and the drive electrode 27,an electrostatic force can be generated between the mass body 60 and thedrive electrode 27. By doing this, the mass body 60 repeats approach andseparation with respect to the drive electrode 27, and it is possible toperform a vertical vibration in which vibration displacement isperformed in the Z-axis direction which is a direction that intersects amain surface. More specifically, by applying an Ac voltage between themass body 60 and the drive electrode 27, the mass body 60 can vibrate inthe Z-axis direction at a predetermined frequency. In the exampleillustrated in FIG. 4, the mass body 60 performs vibration displacementin an α1 direction (−Z-axis direction). In the example illustrated inFIG. 5, the mass body 60 performs vibration displacement in an α2direction (+Z-axis direction) which is a direction opposite to the α1direction (−Z-axis direction).

The mass body 60 on the +X-axis direction side, description of which isomitted has a direction of vibration displacement which is opposite tothe mass body 60 on the −X-axis direction side, and for example, whenthe mass body on the +X-axis direction side performs vibrationdisplacement in the α1 direction (−Z-axis direction), the mass body 60on the −X-axis direction side performs vibration displacement in the α2direction (+Z-axis direction). That is, the mass body 60 on the +X-axisside direction and the mass body 60 on the −X-axis side direction whichare arranged in parallel with each other vibrate in a reverse-phase witheach other.

In a state in which the mass body 60 vibrates in the Z-axis direction,if angular velocity ω of Y-axis rotation is applied to the angularvelocity sensor 100, the Coriolis force is applied to the mass body 60,and the mass body 60 performs vibration displacement in the X-axisdirection. In the example illustrated in FIG. 6, the mass body 60performs vibration displacement in the α1 direction (−Z-axis direction),and thus the mass body 60 performs vibration displacement in a β1direction (−X-axis direction) by the Coriolis force. In the exampleillustrated in FIG. 7, the mass body 60 performs vibration displacementin the α2 direction (+Z-axis direction), and thus the mass body 60performs vibration displacement in a β2 direction (+X-axis direction)which is a direction opposite to the β1 direction (−X-axis direction),by the Coriolis force. For this reason, the detection working electrode40 which extends from the support body 20 that is integral to the massbody 60 also performs vibration displacement in the same direction asthe mass body 60.

If the angular velocity ω of the Y-axis rotation is applied to theangular velocity sensor 100, and thereby the detection working electrode40 performs vibration displacement in the β1 direction (−X-axisdirection), a distance between the detection working electrode 40 andthe detection fixed electrode 50 b is shortened, and a capacitance C2between the detection working electrode 40 and the detection fixedelectrode 50 b increases. In addition, if the detection workingelectrode 40 performs vibration displacement in the β1 direction(−X-axis direction), a distance between the detection working electrode40 and the detection fixed electrode 50 b is lengthened, and acapacitance C1 between the detection working electrode 40 and thedetection fixed electrode 50 b decreases. Thus, if the capacitance C2and the capacitance C1 are respectively converted into voltages by a C/Vconversion circuit (capacitance/voltage conversion circuit, notillustrated), and are amplified by a differential amplifier (notillustrated), it is possible to detect a magnitude of the angularvelocity ω of the Y-axis rotation from an output voltage (AC) of theamplified value.

Even in a case in which the detection working electrode 40 performsvibration displacement in the β2 direction (+X-axis direction), adistance between the detection working electrode 40 and the detectionfixed electrode 50 a, and a distance between the detection workingelectrode 40 and the detection fixed electrode 50 b become reverse tothe distances described above, but in the same manner as describedabove, it is possible to detect a magnitude of angular velocity ω of theY-axis rotation. In addition, by detecting an output voltage of adifferential amplifier using a synchronous detector (not illustrated), arotation direction of angular velocity ω can also be detected.

If a distance in which the mass body 60 performs vibration displacementin the Z-axis direction is lengthened, in a case in which a frequency ofvibration is constant, displacement velocity of the mass body 60 whichvibrates can be increased, and thereby the Coriolis force at the time ofadding the angular velocity increases. For this reason, an amount ofdisplacement of the detection working electrode 40 is also increased,and thereby an amount of change of the capacitance between the detectionworking electrode 40 and the detection fixed electrode 50 can also beincreased, and detection sensitivity can be increased. Thus, it ispossible to obtain the angular velocity sensor 100 having a higherdetection sensitivity.

In the description above, a form (electrostatic driving method) ofdriving the mass body 60 using the electrostatic force is described, buta method of driving the mass body 60 is not particularly limited, and apiezoelectric driving method, an electromagnetic driving method usingLorentz force of a magnetic field, or the like can be applied to themethod.

In addition, in the angular velocity sensor 100 according to the presentembodiment, an AC voltage is applied to the mass body 60 and the driveelectrode 27, the mass body 60 vibrates in the Z-axis direction, andthereby angular velocity of an internal surface axis (Y axis) rotationis detected as a change of a capacitance between the detection workingelectrode 40 and the detection fixed electrode 50. However, in contrastto this, an AC voltage is applied to the detection working electrode 40and the detection fixed electrode 50, the mass body 60 vibrates in theX-axis direction, and thereby angular velocity of an internal surfaceaxis (Y axis) rotation may be configured to be detected as a change of acapacitance between the mass body 60 and the drive electrode 27.

The angular velocity sensor 100 according to the present embodiment has,for example, the following characteristics.

According to the angular velocity sensor 100 of the present embodiment,the mass body 60 can be displaced in a direction which intersects a mainsurface, and thereby the mass body 60 can be easily driven by a verticalvibration which is vibration in a direction (Z-axis direction) whichintersects the main surface. In addition, a distance d1 between thefirst base body 10 and the mass body 60 is lengthened more than adistance d2 between the first base body 10 and the detection fixedelectrode 50, and thereby the mass body 60 which is driven by a verticalvibration can perform a large vibration displacement in the Z-axisdirection which is a direction that intersects the main surface. Thus,since the mass body 60 can be driven by a vertical vibration having alarge amount of displacement (amplitude), in a case in which the angularvelocity of the Y-axis rotation which is an internal surface axis isapplied, a large Coriolis force acts, an amount of change of acapacitance that is generated between the detection working electrode 40and the detection fixed electrode 50 is increased, and thus it ispossible to obtain the angular velocity sensor 100 having a highdetection sensitivity with respect to angular velocity of the Y-axisrotation.

In addition, the mass body 60 is disposed on an upper surface of thethick body section 12 of the first base body 10 through the couplingsection 22, and thereby the mass body 60 can perform a larger vibrationdisplacement up to a distance in which a height of the thick bodysection 12 extending from the first base body 10 is added to thedistance d1 between the first base body 10 and the mass body 60. Inaddition, since the mass body 60 and the thick body section 12 areseparated from each other in a planar view, the mass body 60 can vibratewithout being in contact with the thick body section 12.

In addition, since the detection fixed electrode 50 is provided on anupper surface of the thick body section 12 of the first base body 10,the detection fixed electrode 50 and the detection working electrode 40which extends from the support body 20 that is disposed on an uppersurface of the thick body section 12 of the first base body 10 throughthe coupling section 22 can be disposed so as to face each other, andthereby a capacitance can be formed between the detection workingelectrode 40 and the detection fixed electrode 50.

In addition, a thickness of the detection working electrode 40 isthicker than that of the mass body 60, and thereby it is possible tolengthen a distance in which a main surface of the mass body 60 and amain surface of the first base body 10 face each other, and to increasean area in which the detection working electrode 40 and the detectionfixed electrode 50 face each other. That is, while vibrationdisplacement of the mass body 60 is increased, a capacitance between thedetection working electrode 40 and the detection fixed electrode 50which are electrodes for detection can be increased, and it is possibleto obtain the angular velocity sensor 100 having a high detectionsensitivity.

In addition, by the Coriolis force which is generated by angularvelocity of the Y-axis rotation which is an internal surface axis, themass body 60 performs vibration displacement in the X-axis directionwhich is a direction that intersects a direction in which the detectionworking electrode 40 extends, and thereby the detection workingelectrode 40 which extends from the support body 20 which is coupled tothe mass body 60 also performs vibration displacement in the samedirection as the mass body 60, and an interval between the detectionfixed electrode 50 and the detection working electrode 40 is changed.For this reason, a capacitance between the detection working electrode40 and the detection fixed electrode 50 is changed, and thereby angularvelocity of the Y-axis rotation can be detected by measuring an amountof change of the capacitance between the electrodes.

In addition, since a thickness of the first elasticity section 30 isthicker than a thickness of the second elasticity section 24 in asectional view, a bending stiffness in a thickness direction (Z-axisdirection) of the first elasticity section 30 is higher than that of thesecond elasticity section 24, and thereby, based on vibration in whichthe mass body 60 performs vibration displacement in the Z-axis directionwhich is a direction that intersects a main surface, it is possible tosuppress that the detection working electrode 40 which is coupled to thesupport body 20 performs vibration displacement in the Z-axis direction.

Method of Manufacturing Functional Element

Next, an example of a method of manufacturing the angular velocitysensor 100 as a functional element according to the present embodimentwill be described with reference to FIG. 1, and FIG. 8 to FIG. 11.

The FIG. 8 is a flowchart illustrating important manufacturing processesof the angular velocity sensor 100 according to the present embodiment.FIG. 9 to FIG. 11 are schematic sectional diagrams illustratingmanufacturing processes of the angular velocity sensor 100 according tothe present embodiment.

First Concave Section Forming Process S1

To begin with, in a first concave section forming process (S1), a firstconcave section 14 is formed in a glass substrate 10 a by etching theglass substrate 10 a, and thereby the first base body 10 is obtained.The etching is performed by, for example, wet etching. By the presentprocess, the first base body 10 having the thick body section 12 and thebottom surface 16 can be prepared.

Drive Electrode Forming Process S2

Next, in a drive electrode forming process (S2), as illustrated in FIG.9, the drive electrode 27 is formed on the bottom surface 16 of thefirst concave section 14. A conductive layer is formed on the bottomsurface 16 using a sputtering method, and thereafter the conductivelayer is patterned using a photolithography method and an etchingmethod, and thereby the drive electrode 27 is formed.

Second Concave Section Forming Process S3

Next, in a second concave section forming process (S3), as illustratedin FIG. 10, a second concave section 15 is formed in a silicon substrate110 a by etching the silicon substrate 110 a, and thereby the secondbase body 110 is obtained. The etching is performed by, for example, dryetching. By the present process, the second base body 110 in which thesecond concave section 15 is provided can be prepared.

Bonding Process S4

Next, in a bonding process S4 in which the first base body 10 and thesecond base body 110 are bonged together, as illustrated in FIG. 11, aside in which the first concave section 14 of the first base body 10 isopened, and a side in which the second concave section 15 of the secondbase body 110 is opened are bonded together so as to face each other.Bonding of the first base body 10 and the second base body 110 isperformed by anodic bonding or the like. Areas to be bonded are thethick body section 12 of the first base body 10, the coupling section 22of the second base body 110 which will be formed in the subsequentprocess, and the detection fixed electrode 50. In the bonding process,the first concave section 14 and the second concave section 15 arebonded together in such a manner that openings thereof face each other,and thereby a wide gap in which the mass body 60 can perform a largevibration displacement in the Z-axis direction is configured.

Shape Pattern Forming Process S5

Next, in a shape pattern forming process (S5) in which the couplingsection 22, the support body 20 which includes the first elasticitysection 30 and the second elasticity section 24, the mass body 60, thedetection working electrode 40, and the detection fixed electrode 50 areformed, the second base body 110 is patterned (etched) in a desiredshape, and thereby, the coupling section 22, the support body 20 whichincludes the first elasticity section 30 and the second elasticitysection 24, the mass body 60, the detection working electrode 40, andthe detection fixed electrode 50 are formed. The patterning is performedusing a photolithography technique and etching technology (dry etching),and as a more specific etching technology, a Bosch method can be used.In the present process, by patterning (etching) the second base body110, the coupling section 22, the support body 20 which includes thefirst elasticity section 30 and the second elasticity section 24, themass body 60, the detection working electrode 40, and the detectionfixed electrode 50 are integrally formed.

By the manufacturing method described above, the coupling section 22 isbonded to the thick body section 12, and thereby the support body 20 inwhich the first elasticity section 30 and the second elasticity section24 are included, the mass body 60, and the detection working electrode40 can be separated from the first base body 10, and it is possible toperform vibration displacement of the mass body 60 in the Z-axisdirection, or vibration displacement of the detection working electrode40 in the X-axis direction.

In addition, the detection fixed electrode 50 is bonded to the thickbody section 12, and thereby it is possible to easily perform anelectrical insulation of the detection working electrode 40 and thedetection fixed electrode 50, and to easily form a capacitance betweenthe detection working electrode 40 and the detection fixed electrode 50.

As described above, according to the method of manufacturing the angularvelocity sensor 100 according to the present embodiment, the mass body60 is formed in the second concave section 15 which is formed in thesecond base body 110, in the shape pattern forming process in which thecoupling section 22, the support body 20, the mass body 60, thedetection working electrode 40, and the detection fixed electrode 50 areformed. For this reason, a distance between a main surface of the massbody 60 and a main surface of the first base body 10 can be lengthened,the mass body 60 can perform a large vibration displacement in adirection which intersects the main surface of the mass body 60, andthereby it is possible to manufacture the angular velocity sensor 100having a high detection sensitivity.

In addition, the method of manufacturing the angular velocity sensor 100according to the present embodiment includes the first concave sectionforming process in which the first concave section 14 is formed in thefirst base body 10. In the drive electrode forming process, the driveelectrode 27 is formed in the first concave section 14. In the bondingprocess, the first concave section 14 of the first base body 10 and thesecond concave section 15 of the second base body 110 are bondedtogether so as to face each other. For this reason, the mass body 60 andthe drive electrode 27 can be disposed so as to face each other, a gaparea in which the mass body 60 can perform vibration displacement isfurther widened, the mass body 60 can perform a larger vibrationdisplacement in a direction (Z-axis direction) which intersects a mainsurface, and thereby it is possible to manufacture the angular velocitysensor 100 having a high detection sensitivity.

Electronic Apparatus

Next, an electronic apparatus which includes the functional elementaccording to an embodiment of the invention will be described in detailusing FIG. 12 to FIG. 14. In the present description, an example inwhich the angular velocity sensor 100 is used as a functional element isillustrated.

FIG. 12 is a perspective diagram illustrating a schematic configurationof a personal computer of a mobile type (or notebook type) as an exampleof an electronic apparatus which includes the angular velocity sensor100 according to an embodiment of the invention.

In FIG. 12, a personal computer 1100 is configured to include a bodysection 1104 which includes a key board 1102, and a display unit 1106which includes a display section 1000. The display unit 1106 issupported so as to be able to rotate with respect to the body section1104 through a hinge structure section. The angular velocity sensor 100which includes a function in which an angle at the time of rotating thepersonal computer 1100 is detected is embedded in the personal computer1100.

FIG. 13 is a perspective diagram illustrating a schematic configurationof a mobile phone 1200 (including PHS) as an example of an electronicapparatus which includes the angular velocity sensor 100 according to anembodiment of the invention.

In FIG. 13, the mobile phone 1200 includes a plurality of operationbuttons 1202, a voice receiving hole 1204, and a voice transmitting hole1206. The display section 1000 is disposed between the operation buttons1202 and the voice receiving hole 1204. The angular velocity sensor 100which includes a function in which an angle at the time of rotating themobile phone 1200 is detected is embedded in the mobile phone 1200.

FIG. 14 is a perspective diagram illustrating a schematic configurationof a digital still camera 1300 as an example of an electronic apparatuswhich includes the angular velocity sensor 100 according to anembodiment of the invention. FIG. 14 also simply illustrates with regardto a connection to an external apparatus. Here, while a film camera inthe related art exposes a silver salt photographic film to light usingan optical image of a subject, the digital still camera 1300 performs aphotoelectric conversion of the optical image of the subject using animaging device such as a charge coupled device (CCD) and generates animaging signal (image signal).

The display section 1000 is provided on a back surface of a case (body)1302 of the digital still camera 1300, and display is performed based onan imaging signal according to the CCD. The display section 1000functions as a finder which displays the subject as an electronic image.In addition, a light receiving unit 1304 which includes an optical lens(imaging optical system), a CCD or the like is provided on a frontsurface side (rear side in the figure) of the case 1302.

If a photographer checks a subject image which is displayed on thedisplay section 1000 and pushes a shutter button 1306, an imaging signalof the CCD at that time is transferred to a memory 1308 and is storedthere. In addition, in the digital still camera 1300, a video signaloutput terminal 1312, and an input and output terminal 1314 for datacommunication are provided on a side surface of the case 1302. Then, asillustrated, a television monitor 1430 is connected to the video signaloutput terminal 1312, and a personal computer 1440 is connected to theinput and output terminal 1314 for data communication, as necessary.Furthermore, the digital still camera 1300 is configured such that animaging signal which is stored in the memory 1308 is output to thetelevision monitor 1430 or the personal computer 1440 by a predeterminedoperation. The angular velocity sensor 100 which includes a function inwhich an angle at the time of rotating the digital still camera 1300 isdetected is embedded in the digital still camera 1300.

In addition to the personal computer 1100 (mobile type personalcomputer) of FIG. 12, the mobile phone 1200 of FIG. 13, and the digitalstill camera 1300 of FIG. 14, the angular velocity sensor 100 accordingto an embodiment of the invention can also be applied to an electronicapparatus, such as a mobile terminal such as a smart phone, acommunication apparatus, an ink jet type ejecting device (for example,ink jet printer), a laptop type personal computer, a tablet typepersonal computer, a storage area network apparatus such as a router ora switch, a local area network apparatus, an apparatus for a mobileterminal base station, a television, a video camera, a video recorder, acar navigation device, a real time clock device, a pager, an electronicnotebook (including a communication function), an electronic dictionary,an electronic calculator, an electronic game machine, a word processor,a workstation, a videophone, a security television monitor, electronicbinoculars, a POS terminal, a medical apparatus (for example, anelectronic thermometer, a blood pressure monitor, a blood glucose meter,an electrocardiogram measuring device, an ultrasonic diagnostic device,an electronic endoscope), a fish finder, various measuring instruments,gauges (for example, gauges of a vehicle, an airplane, and a ship), aflight simulator, a head-mounted display, a motion trace, motiontracking, a motion controller, or a pedestrian position orientationmeasurement (PDR).

Mobile Object

Next, a mobile object which includes a functional element according toan embodiment of the invention will be described using FIG. 15. In thepresent description, an example in which the angular velocity sensor 100that is used as a functional element is used will be described.

FIG. 15 is a perspective diagram schematically illustrating anautomobile 1500 as an example of a mobile object.

The angular velocity sensor 100 according to an embodiment of theinvention is mounted in the automobile 1500.

As illustrated in FIG. 15, the angular velocity sensor 100 is embeddedin the automobile 1500 which is used as a mobile object, and thereby anelectronic control unit 1502 which controls a tire 1503 or the like ismounted in a car body 1501. In addition, in addition to those describedabove, the angular velocity sensor 100, can be widely applied to anelectronic control unit (ECU), such as a keyless entry, an immobilizer,a car navigation system, a car air conditioner, an anti-lock brakesystem (ABS), an airbag, a tire pressure monitoring system (TPMS), anengine control, a brake system, a battery monitor of a hybrid automobileor an electric vehicle, or a vehicle body posture control system.

The entire disclosure of Japanese Patent Application No. 2014-121216,filed Jun. 12, 2014 is expressly incorporated by reference herein.

What is claimed is:
 1. A functional element comprising: a first basebody; a coupling section which is coupled to the first base body; asupport body which extends from the coupling section; a mass body whichis coupled to the support body; a drive electrode which is provided on asurface side that faces the mass body of the first base body; adetection working electrode which extends from the support body; and adetection fixed electrode which is coupled to the first base body andfaces at least a portion of the detection working electrode, wherein themass body can be displaced in a direction which intersects a mainsurface of the mass body, and wherein, when a distance between the firstbase body and the mass body is referred to as d1 and a distance betweenthe first base body and the detection fixed electrode is referred to asd2, a relation of d1>d2 is satisfied.
 2. The functional elementaccording to claim 1, wherein a thick body section is provided in thefirst base body, the coupling section is provided in the thick bodysection, and in a planar view, the mass body and the thick body sectionare separated from each other.
 3. The functional element according toclaim 2, wherein at least a portion of the detection fixed electrode isprovided in the thick body section.
 4. The functional element accordingto claim 1, wherein a thickness of the detection working electrode isthicker than that of the mass body.
 5. The functional element accordingto claim 1, wherein, when the mass body is vibrated by an AC voltagewhich is applied between the mass body and the drive electrode, andangular velocity of axis rotation in a direction along the main surfaceof the mass body and the direction in which the detection workingelectrode extends is applied to the mass body, the detection workingelectrode vibrates in a direction which intersects the direction.
 6. Thefunctional element according to claim 1, wherein the support bodyincludes a first elasticity section which is coupled to the couplingsection, and a second elasticity section which is coupled to the massbody, and wherein a thickness of the first elasticity section is thickerthan a thickness of the second elasticity section, in a sectional view.7. A method of manufacturing a functional element, comprising: forming asecond concave section in a second base body by processing the secondbase body; disposing a drive electrode on a first base body; bondingtogether a surface having the second concave section which is providedin the second base body and a surface having the drive electrode of thefirst base body; and forming a coupling section, a support body, a massbody, a detection working electrode, and a detection fixed electrode byprocessing the second base body, wherein, the forming of the couplingsection, the support body, the mass body, the detection workingelectrode, and the detection fixed electrode includes forming the massbody in the second concave section.
 8. The method of manufacturing afunctional element according to claim 7, further comprising: forming afirst concave section in the first base body, wherein the disposing ofthe drive electrode includes forming the drive electrode in the firstconcave section, and wherein the bonding includes bonding together thefirst concave section and the second concave section so as to face eachother.
 9. An electronic apparatus comprising: the functional elementaccording to claim
 1. 10. A mobile object comprising: the functionalelement according to claim
 1. 11. The functional element according toclaim 2, wherein a thickness of the detection working electrode isthicker than that of the mass body.
 12. The functional element accordingto claim 3, wherein a thickness of the detection working electrode isthicker than that of the mass body.
 13. The functional element accordingto claim 2, wherein, when the mass body is vibrated by an AC voltagewhich is applied between the mass body and the drive electrode, andangular velocity of axis rotation in a direction along the main surfaceof the mass body and the direction in which the detection workingelectrode extends is applied to the mass body, the detection workingelectrode vibrates in a direction which intersects the direction. 14.The functional element according to claim 3, wherein, when the mass bodyis vibrated by an AC voltage which is applied between the mass body andthe drive electrode, and angular velocity of axis rotation in adirection along the main surface of the mass body and the direction inwhich the detection working electrode extends is applied to the massbody, the detection working electrode vibrates in a direction whichintersects the direction.
 15. The functional element according to claim4, wherein, when the mass body is vibrated by an AC voltage which isapplied between the mass body and the drive electrode, and angularvelocity of axis rotation in a direction along the main surface of themass body and the direction in which the detection working electrodeextends is applied to the mass body, the detection working electrodevibrates in a direction which intersects the direction.
 16. Thefunctional element according to claim 2, wherein the support bodyincludes a first elasticity section which is coupled to the couplingsection, and a second elasticity section which is coupled to the massbody, and wherein a thickness of the first elasticity section is thickerthan a thickness of the second elasticity section, in a sectional view.17. The functional element according to claim 3, wherein the supportbody includes a first elasticity section which is coupled to thecoupling section, and a second elasticity section which is coupled tothe mass body, and wherein a thickness of the first elasticity sectionis thicker than a thickness of the second elasticity section, in asectional view.
 18. The functional element according to claim 4, whereinthe support body includes a first elasticity section which is coupled tothe coupling section, and a second elasticity section which is coupledto the mass body, and wherein a thickness of the first elasticitysection is thicker than a thickness of the second elasticity section, ina sectional view.
 19. The functional element according to claim 5,wherein the support body includes a first elasticity section which iscoupled to the coupling section, and a second elasticity section whichis coupled to the mass body, and wherein a thickness of the firstelasticity section is thicker than a thickness of the second elasticitysection, in a sectional view.
 20. The functional element according toclaim 14, wherein the support body includes a first elasticity sectionwhich is coupled to the coupling section, and a second elasticitysection which is coupled to the mass body, and wherein a thickness ofthe first elasticity section is thicker than a thickness of the secondelasticity section, in a sectional view.